The PO or the PPO or the PPPO installed a later model rear relay on my 4104. I had not been concerned about this 'til I read a post about someone's bus where a "bobtail" (?) relay had been installed instead of a proper relay. Well the rear relay on my bus looks truckish, no numbers that I can see, maybe someone recognizes it. Barring that I will do some pressure tests making sure relay boosts at the same rateas the application valve. As always thanks for the input.I'm shameless my helper after cleaning up

I have a few from last winter. This was the 76 mtl olympics bus, my gus guy said there's is talk of tarting it up and sending out to vancouver for the olympics...it's pretty rough but there's enough stuff around he could do it. Saw my first V6-92 changed out of a transit yesterday, not as easy as it's sounds but I guess easier than it could be.

Air valve looks Bendix, kinda like a R-6...that's a place to start anyway. Looking again, the bottom is not R-6 as R-6 has four delivery ports on bottom, but the domed top is similar.

If the valve only has the four lines, probably the large one (shiney brass) is supply from an air tank, the smaller one is signal (from your brake pedal) and of course the bottom two are delivery...no problem with the compounding issue. I am assuming this is a service brake relay valve...yes?

Air valve looks Bendix, kinda like a R-6...that's a place to start anyway. Looking again, the bottom is not R-6 as R-6 has four delivery ports on bottom, but the domed top is similar.

If the valve only has the four lines, probably the large one (shiney brass) is supply from an air tank, the smaller one is signal (from your brake pedal) and of course the bottom two are delivery...no problem with the compounding issue. I am assuming this is a service brake relay valve...yes?

I guess I shoulda stuck with my first impression! I think the RE-6 has the four ports, two 1/4" & two 3/8"